Medicated sponges are used during open surgery to stop local bleeding (hemostasis/haemostasis). They react upon contact with blood, other body fluids or saline to form a clot that glues the sponge to the tissue surface and hemostasis is reached in a few minutes. Medicated sponges are sponges, such as a collagen carrier as defined below, such as a cellulose sponge as disclosed in EP2052746.
Collagen has been used as a haemostatic agent for decades. A product that combines the haemostatic features of fibrin glue with the asset of collagen as a carrier has been developed and manufactured under the trademark TachoSil®. TachoSil® is a ready-to-use collagen carrier with a coating of the active components of fibrin glue: human fibrinogen and human thrombin. The product is described in WO 02/058 749, WO 02/070 594 and WO 02/058 750.
TachoSil® contains fibrinogen and thrombin as a dried coating on the surface of a collagen sponge. In contact with body fluids, e.g. blood, lymph or physiological saline solution the components of the coating dissolve and partly diffuse into the wound surface. This is followed by the fibrinogen-thrombin reaction which initiates the last phase of physiological blood coagulation. Fibrinogen is converted into fibrin monomers which spontaneously polymerise to a fibrin clot, which holds the collagen sponge tightly to the wound surface.
TachoSil® has been sold since 2004 by Nycomed and is used in open surgery for hemostasis and sealing. Traditional open surgery usually requires a long incision of the skin.
Contrary to open surgery, a minimally invasive procedure is any procedure (surgical or otherwise) that is less invasive than open surgery used for the same purpose. Minimally invasive surgery (MIS) procedures are performed through one or more access orifices e.g. short incisions (‘keyhole surgery’) or through natural body openings. Hence, MIS procedures require specially designed surgical instruments which are placed through these access orifices. In abdominal surgery, the access of the instruments is usually done through so-called trocars, which are mostly rigid tubes with a typical inner diameter of 5 to 12 mm. The small size of the access orifices used in MIS restricts what can be inserted into the orifices. Therefore, all surgical tools and materials used in MIS procedures must be of a size and condition that allow for their insertion through the access orifices and they need, of course, as all medical tools to be sterile. Hence, tools and materials are most often specially designed for use in MIS.
WO 97/21383 (Nycomed Arzneimittel GmbH) discloses a surgical instrument comprising an applicating member, wherein the applicating member comprises a rodshaped portion so as to allow a sheet of surgical material such as, e.g. TachoComb® (coated equine collagen sponge/Nycomed) to be rolled up to form a carpetlike roll of surgical material on the rod-shaped portion of the applicating member. However, this manual instrument for hand-rolling surgical materials, such as collagen carriers, has several disadvantages as described below. WO 02/058749 discloses the non-sterile insertion of TachoComb® into an endoscopic equipment, wherein the sample is flattened manually to be able to wrap it manually around a guiding “pin”. WO 02/058749 teaches that the collagen product “has to stay flexible enough in dry condition to be bent and rolled up” (p29, lines 19-20). Thus WO 02/058749 only relates to manual (i.e. hand-rolled), non-sterile rolling of TachoComb® and further teaches that the rolling process must be “dry”. One significant problem with the above methods which use an applicating member or guiding pin for hand-coiling the collagen carrier arises in case application of multiple rolled/coiled collagen carriers is necessary in quick succession (e.g. either because one collagen carrier is insufficient to completely stop the bleeding, or due to an error in application of the first collagen carrier(s)). In this instance the same applicating member cannot be used to apply the second collagen carrier: instead, multiple applicating members must be prepared. This is because in order to apply collagen-based products such as the TachoComb® product correctly, the applicating member must be completely dry in order to avoid activating the adhesive properties of the collagen carrier. If the collagen carrier becomes prematurely wet by contacting a wet application member or guiding pin, the carrier will stick to the applicating member/guiding pin and/or become an unusable sticky lump of material. Another way of rolling up collagen-based surgical sheets is for the surgeon to use his/her hands in the same way as for rolling up a cigarette, however for this and all the manually-rolled cases above the rolled surgical product is not form-stable and is therefore more difficult to manipulate in a controlled manner after insertion into the body: the non-form-stable product may “spring open” in an uncontrolled way during the unrolling process and adhere incorrectly. This is a particular issue for MIS surgery, where it is harder to manipulate the product once it is in the body as one only has indirect access to the surgical sheet via endoscopic surgical instruments. One way of lessening the effect of the rolled collagen-based surgical product being non-form-stable is to tie the rolled product together with a suture, however this solution is only relevant where the coiled carrier in not unrolled in vivo but rather maintained in the patient in a coiled state (e.g. in a partial nephrectomy procedure).
For applications such as MIS there is thus a need to produce an improved coiled collagen-based surgical product, which has dimensions useful for MIS applications and useful properties for promoting coagulation and wound sealing, but which allows easy application of more than one collagen carrier in quick succession and furthermore gives the surgeon improved control of the complex process of moving the carrier to the desired tissue site and applying it.
A further problem with all the above types of manual coiling processes for collagen carriers is that the results are of course highly dependent on the skills of the individual medical practitioner carrying out the coiling process, and therefore highly variable in reproducibility, and may lead to a non-sterile product, un-even and thus un-reproducible coiling/rolling of the collagen carrier, and un-predictable loss of coating.
Thus, there exists a need in the art for a collagen carrier coated with human fibrinogen and human thrombin especially designed for use in minimally invasive surgery that is ready-to-use, maintains sterility, and which has an acceptable hemostatic and tissue sealing effectiveness and adhesive strength to living tissue, and also which allows easy application of more than one collagen carrier in quick succession for MIS techniques, and also allows the surgeon more control on application to the desired tissue during an MIS procedure in order to avoid adhesion of the collagen carrier to an incorrect site, would be advantageous.
Hence, a ready-to-use collagen carrier coated with human fibrinogen and human thrombin designed particularly for use in MIS, such as designed to fit an access tube and/or orifice in MIS, preferably such as to be inserted into endoscopic devices would be advantageous, and in particular a ready-to-use collagen carrier coated with human fibrinogen and human thrombin having an acceptable hemostatic effectiveness, adhesive strength to living tissue and sterility that is ready-to-use in MIS, allows easy application of more than one collagen carrier in quick succession for MIS techniques, and also allows the surgeon more control on application to the desired tissue during an MIS procedure in order to avoid adhesion of the collagen carrier at the incorrect site, would be advantageous.